Abrading or buffing pad



Feb. 27, 194s. A' G, D, E 21,370,491

ABRADING OR BUFFING PAD Filed Aug, 2l, 1943 y j K @gc/)18e 4allge@ pad.

Petenfeei Feb. 27.1945

UNITED ,STATES PATENT OFFICE ABRADING on BUFFING PAD George D. mee, chicago, n1.

Application August 21, 1943, Serial No. 499,481

15 Claims.

The invention relates to abrading or bumng devices and more particularly to an improved multi-ply abrasive pad adapted for use with a rotatably driven shaft or mandrel.

ing pad constructed of abrasive sheets for-med' with uncoated central areas which permit the plies to besecured together by stitching Without excessive wear on the needle and which enable the individual plies to flex into conformity with the surface being operated on without cracking orotherwisel injuring the relatively`stiff abrasive coating. v

Still anotherobject is to provide an abrading pad built up of a plurality of sheets of. abrasive coated material in which the sheets are arranged in a novel manner so that the abrasive coating is presented for action when the .pad isrotated in either direction about an 'axis extending lengthwise of the pad.

It is also an object of the invention to provide an abrading or bufling pad adapted to function efficiently in finishing a wide variety of irregular surfaces including bores and recesses of different shapes and sizes which is relatively inexpensive to manufacture.

Other objects and advantages of the invention will become apparent from the following detailed e description of the `preferred embodiment, illustrated in the accompanying drawing in which:

Figure 1 is a perspective View of an improved abrading and bufling pad shown as mounted on a mandrel. l

Fig. 2 is a side elevational view of the pad with sections of successive plies broken away to show the manner in Which they are assembled.

Fig. 3 is an end view of the device as used innishing the interior surface off the circular bore. Fig. 4 is a side View of a modified form of the Referring to the 'drawing the improved pad is built up of a plurality of sheets or plies 5 consisting of a exible backing-strip such as cloth having a facing B of abrasive particles on at least one side. The sheets 5 are arranged one above the other in a stack and secured together along a central axis to form a central hub portion 1 with diametrically opposed projecting wing portions 8 and 9. In the form illustrated in Figs. 1, 2 and 3, the sheets 5 are provided with the abrasive facing yli on one side only and the hub portion is defined by two parallel rows of stitching I0 extending longitudinally of the stack of sheets and spaced apart to permit the insertion of a mandrel Il therebetween.

While the backing strips forming thev plies 5 may be made of any suitable material, it is preferred to use closely woven clothto which abrasive facing may be applied in any suitable manner. The abrasive facing may -be provided on one or both sides of the backing strip a'srrequired thus. l forming either single or double coated plies. Plies` having an abrasive facing on one side only are assembled in a novel manner so asto permit easy slippage between adjacent plies and so that the abrasive facing is presented on the leading surface of both wing portions 8 and 9 when'the pad is rotated about its axis. To this end, the plies `are divided into two equal piles each having the abrasive faced sides of the pliessimilarly ac-v cented. 'I'hus the faced side of one ply rests. against the uncoated side of the next adjacent.

ply, thereby permitting easy slippage betweenadjacent plies so that the pad may be flexed readily when twisted into the shape required to enter the plies face 'in one direction while the coatings of the other half of the sheets face inthe opposite direction as clearly shown in Fig. 2. An labrasive clear, relatively nexible section adapted to func-- tion in the manner of a hinge. In the exemplary pad, each of the plies 5 is formed with a clear central section l5 preferably of sufficient width to leave a marginal hinge portion I6 between each row of stitches I0 and the wing portions 8 and 9. yThe wing portions of the plies may thus be bent sharply in either direction as shown in of the stack of plies to form the pad. Since the v stitching I is confined to the clear area l5, a

Y minimum of resistance is offered to the passage (f the needle utilized in performing the stitching operation and excessive wear of the same is effec'- tually avoided. Also any danger o f the threads being cut by the abrasive is avoided.

In operation, a pad of the type shown in Figs. 1, 2 and 3 is mounted on a suitablefniandrel or shaft and rotated at high speed. As the outer edges of the rotating pad engage the surface of` the work, the wing portions 8 and 9 bend in opposite directions, the plies 5 slipping over each other in the manner of the pages of a book to expose a narrow strip of the coated face 6 of each ply for action on the Work. As the edges of the plies 5 wear away, a fresh area of abrasive is presented to the work, thus enabling the pad to operate efficiently until worn down closely adjacent the hub portion 'l'.

To facilitate the flexing of the pad incident to its insertion into a bore it of smaller diameter than the pad, the plies ti forming the pad are preferably out with their forward end portions tapering substantially to a point as indicated at l1. With the tapered formation, bending of the plies 5 begins only after the forward end portion of the pad has been inserted in the bore and such bending increases gradually until the pad is fully against the surface of the Work will depend, of

course, upon the diameter to which the pad is reduced when inserted in the work.

faces of the plies on each side of the axis present their abrasive facing for action on the work. The remainder of the plies present their uncoated or clear surfaces which perform a wiping or bufling action and thus contribute to the production of a smooth finish on the work. The action of the pad is exactly the same on both sides of its rotational axis due to the novel manner in which the plies are assembled. Moreover, 'the same action results when ,the pad is rotated in either direction. Fig. 4 illustrates certain modifications that may be made in the construction of the pad to better Yadapt it for certain specific operating conditions.

Thus, the double tapered form of the pad as shown in this figure particularly adapts it for use von relatively thin work as explained above.

be assembled when provided with an abrasive facing 6a on both sides. Under these conditions a plain fabric ply 5a is interposed between adjacent abrasive faced plies 5 to permit easy slip. page of the plies when the pad is inserted ina bore.

In the modified form of the pad, the plies 5 are secured together by a. single row of stitching Illa. The pad is thus adapted to be held in a suitable clamp, as for example a split mandrel. As in the previous instance, the plies are formed with a clear, flexible central section which functions as a hinge for the purpose heretofore explained.

In either type of pad above described, the abrasive facings 6 or Ga may be of diierent grades or different degrees of iineness on opposite wings 8 and 9 of the respective plies. With this construction, an abrasive facing of one grade is presented to the work 'when the pad is rotated in one direction while an abrasive facing of a different grade is presented when the pad is rotated in the opposite direction. Both a roughing and finishing operation can therefore be performed with the same pad.

fn the form shown in Fig. 1; only the first half of the leading I Fig. 4 also shows the manner in which the plies 5 may It Will be apparent from the foregoing that the invention provides an abrading or buing Dad of novel and improved construction. By utilizing abrasive faced sheets or plies having a clear, flexible central area, the stack of sheets may be stitched together without excessive wear on the needle. Bending of the sheets is facilitated by the hinge-like action of the clear areas thus avoiding cracking of the abrasive facing.

Due to the novel manner in which the plies are assembled, an abrasive surface is presented for action on the work on the leading faces of the wing portions of the pa-d, that is, on both sides of the rotational axis and when the pad is rotated in either direction. Insertion of the pad into a relatively small bore or recess is facilitated by the tapered construction of the sheets forming the same. n general, the abrading or buing pad constructed in accordance with the present invention is an inexpensive yet efficient and reliable tool for finishing irregular surfaces and .particularly bores and recesses of different shapes an-d diameters.

I claim as my invention:

` l. A multi-ply abrading pad comprising, a plun rality of iiexible plies assembled in a stack, each of said plies having an abrasive facing cnlone side only, and means securing the stack of pliesV together along a central axis to provide oppositely disposed wing sections projecting radially from the axis and in a common plane therewith.

2. An abrading pad comprising, a plurality of flexible plies assembled in a stack, each of said plies having an abrasive coating on atleast one side', and means securing the. plies together to form a central hub portion extending longitudinally of the stack and a pair of wing portions projecting radially from opposite sides of said hub portion, said hub portion being adapted to receive a rotatably driven mandrel.

3. An abrading pad comprising, a plurality of iiexible plies assembled in a stack, a relatively stiff abrasive facing on at least one side of each ply, and means securing the stack of plies together along an axis extending longitudinally of the stack, each of said plies being weakened toV provide a hinge section adjacent said axis.

4. An abrading pad comprising, a plurality of :flexible abrasive faced plies assembled'in a stack,

means securing the plies together along an axis extending longitudinally of the stack, each of said plies having a clear section adjacent the axis adapted to bend easily and thereby permit substantial flexing' of the pad without injury to the abrasive facings of the plies.

5. An abrading pad comprising, a plurality of flexible abrasive faced plies assembled in a stack, stitching extending across the central portion of the stack to secure the'plies together, said central portion o-f each ply being clear of abrasive to facilitate bending of the plies substantially along the line of said-stitching.

6. An abrading pad comprising, a plurality of flexible plies assembled in astack and secured4 together by spa/ced parallel rows of stitching ex tending across the stack along a central axis, each of said plies having an abrasive facing on one side only extending from the outer edge of ingrwing portions, said plies being assembled in back-to-back relation s o that the abrasive facing is presented on the leading surface of each Wing portion when the Wing portions are reversely) bent as thepad is rotated about said axis.

8. An abrading pad comprising, a pluralityA of flexible plies each coated on 'one side only with abrasive material and arranged in a stack,'and ymeans securing the stack of plies together along a central axis, said stack being divided into two Wardly of the stack-- 1l. An abrading pad comprising, a plurality of flexible plies arranged in a stack, each of said plies having on one side only a facing of abrasive `30 substantially equal sections with the abrasive -surfaces of the plies of each section facing out- 9. An abradirig pad comprising, a plurality of *n iiexible plieseach faced on one side with abrasive material and arranged in a stack, and means securing the stack of plies together along a-central axis to denne oppositeiy disposed wing por- Y tionsprojecting radially from the axis and in a common plane therewith, said plies being assembled in back-to-backv relation so that in each wingv portion substantially equal numbers of plies present their abrasive faced and unfaced sides respectively inthe direction in whichthe wing portion advances when the pad is rotated aboutv l said axis.

10. An abradingvv and :bung pad comprising, a stack of flexible pliessecured together along a central axis extending longitudinally of the stack and forming a pair of oppositely disposed radially projecting wing portions of Vsubstantially the same dimensions, and a facing of abrasive material on one side of each'ply, said plies being assembled in `a manner such` that one or more of the plies adjacent lthe leading surface of each wing portion perfor-ms an abrading Operation `while the remainder of the plies perform a buffing operation when the pad is rotated about said axis in operative engagement with a workpiece.A

material extending from opposite side edges of the ply4 to a clear area extending longitudinally of the ply, spaced paralle1 rows of stitching .mthin the clear areas securing the stack of plies together and .defining a central hub portion adapted to receive a rotatably driven mandrel, said plies being assembled so that the abrasive surfaces of one or more sheets is presented on the leading face of the pad on each side of the mandrel. f f

12. An abrading pad comprising, a stack of flexible plies secured together'along, a central axis by parallel rows of stitching dening /a hub portion and oppositely disposed radially projecting Wing portions, each of said plies having the wing portions faced on one side only with abrasive material, said rows of stitching being spaced from the abrasive faced areas so as to. leave a clear marginal area therebetween for easy Ibending of the plies, said plies being assembled in the stack with the abrasive faced sides of one half of the plies facing in one direction and the abrasive faced sides ofthe other half facingin the opposite direction whereby an abrading snface is presented on the leading face of each wing portion when the pad is 'rotated about said hub portion.

l13. A multi-ply abrading pad comprising, a

I4. A multi-ply abrading pad comprising, a

plurality of exible plies assembled in a stack,

-means securing the stack of plis together along an axis extending longitudinally of the stack to dene opposed radially projecting wing portions, and an abrasive facing, on at least one side of the wing portions of one or more of said plies, the

abrasive faoings of opposite .wing portions of one ply being of different grades. 15.v An abrasive element of flexible material adapted to be supported for rotation about a central longitudinal axis and presenting a. stack of sheets providing radially projecting wing portions engageable with oppositel sides of a hollow cylindrical workpiece, said wing portions having an abrasive coating on at least one side in back-toback relationship and being tapered` at one end to facilitate insertion of the element into a workpieceV having a diameter less than the Width of the'element; i

' GEORGE D. RICE. 

